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本文用积分固定床反应器对异丁烯-甲醛一步缩合制异戊二烯用Cr-P/SiO_2催化剂的失活动力学进行了研究,测定了在反应温度为260～340℃,常压及不同反应物组成时的反应速度。建立了失活动力学方程,估算出反应级数、活化能、以及失活级数和失活因子。所得失活动力学方程式为: r=1.07x10~(-6)exp(-35.2/RT)·P_1~0.9·P_2~1.5·a a=0.47+0.53exp(-4.83×10~(-4)t) -da/dt=2.56×10~(-4)exp(-4.83×10~(-4)t) 从上述方程式推测,在Cr-P/SiO_2催化剂上可能存在两种活性中心,一种是既能进行缩合反应同时又伴随积炭的中心,另一种中心则只进行缩合反应。催化剂的失活机理为反应物没有内扩散阻力的平行—串联失活,反应物与产物均能在催化剂表面形成焦炭,覆盖活性中心或堵塞洞口而导致失活。经烧炭催化剂活性可获得恢复。
In this paper, the kinetics of Cr-P / SiO 2 catalyst deactivation by isothermal condensation of isobutylene-formaldehyde to Cr-P / SiO 2 catalyst was investigated using integral fixed bed reactor. The reaction kinetics of Cr- Composition of the reaction speed. The kinetic equation of inactivation was established to estimate the reaction order, activation energy, deactivation order and inactivation factor. The kinetic equation of inactivation was: r = 1.07 × 10 -6 exp (-35.2 / RT) · P 1 ~ 0.9 · P 2 ~ 1.5 · aa = 0.47 + 0.53exp (-4.83 × 10 -4 t) -da / dt = 2.56 × 10 -4 exp (-4.83 × 10 -4 t) From the above equation, it is presumed that there may exist two kinds of active sites on the Cr-P / SiO 2 catalyst, Condensation reaction can be carried out at the same time with the center of coke, the other center only for condensation reaction. The deactivation mechanism of the catalyst is parallel-series deactivation in which the reactants have no internal diffusion resistance. Both reactants and products can form coke on the surface of the catalyst, covering the active center or blocking the hole and causing inactivation. After the charcoal catalyst activity can be restored.